Alternating-current arc-lamp.



PATENTED MAY 26. 1903. M. 'H. BAKER. ALTERNATING CURRENT ARC LAMP. APPLICATION FILED JUNE 26 1902 10 MODEL.

M gmwmop i-twaooeo UNITED STATES Patented May 26, 1903.

PATENT OFFICE.

MALCOLM H. BAKER, OF EAST LIBERTY, PENNSYLVANIA, ASSIGNOR T0 \VESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A COR- PORATION OF PENNSYLVANIA.

ALTERNATlNG-CURRENT ARC-LAM P.

SPECIFICATION forming part of Letters Patent No. 729,114, dated May 26, 1903. Application filed June 26, 1902. Serial No. 113.211. (No model.)

To aZZ whom, it may concern:

Be it known that I, MALCOLM H. BAKER, a citizen of the United States, and a resident of East Liberty, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Alternating-Current Arc-Lamps, of which the follow ing is a specification.

In the well-known Bremer arc-lamp, wherein the arc itself, in distinction from the electrode-points, supplies the main portion of the light, it has been customary to control the shape and stability of the are by means of blower-magnets, and the same sourcesof influence have been applied to the are for the purpose of regulating its resistance and at the same time the resistance of the lamp. This has been accomplished by placing an iron core in proper relation to the electrodepoints or the arcing space between them, winding the said core with coarse wire in series with the electrodes and with finer wire placed in a shunt across the arc. The two windings are so arranged as to oppose each other electrically, and the coarse-Wire winding is so laid as to magnetize the core with a force attracting the arc-that is to say, when the magnetization of the core due to the current in the coarse-wire winding is largely preponderating over that due to the current in the fine-wire winding the arc will be strongly attracted and will be drawn out into a fan shape, thereby raising the arc voltage. On the other hand, when the magnetization due to the current in the fine-Wire winding grows comparatively large the total attraction of the core will be diminished, the arc will recede, and the arc voltage will be decreased. Manifestly these described actions take place in the order named whenever, first, the lamp takes too much current and whenever, second, the lamp voltage becomes too highthat is to say, the tendency of the difierential action of the two coils on the magnetic blow-out core is to keep the resistance of the arc normal by lengthening the are when the lamp resistance becomes too small and the current through the coarse-wire winding increases and by shortening the are when the lamp resistance becomes excessive and the current through the fine-wire winding increases. This action of a differentiallywound magnet is valuable in certain classes of direct-current service; but it is impossible to use such a device for alternating-current work, since one of the windings would become a closed transformer secondary of which the other winding is the primary. In using such a device in connection with an alternating-current arclamp the coil would be burned out and the de vice would be inoperative.

The present invention relates to means for accomplishing in an alternating-current arclamp the same results as those eifected by the device described above.

By mounting the series and shunt windings upon separate cores and bringing these cores or extensions thereof into such relation to the arc and to each other that the magnetic fields of the two coils act differentially upon each other I am able to keep the inductive actions of the two windings independent and at the same time to produce a differential magnetic regulating-field for controlling the arc resistance. In other words, I avoid the inductive transformer action which would exist if both coils were mounted upon a common core, and I also obtain the regulation which I desire. In this case, as before, the windings are so connected that the field from the series core attracts the arc,while the field from the shuntcore, acting in opposition to the other field, cuts down the attraction and causes a shortening or receding of the arc.

My invention will be clearly understood. by reference to the accompanying drawings, in which Figure l is a plan, and Fig. 2 an elevation, of a pair of arc-lamp electrodes, the are between them, and the series and shunt magnets and cores whereby I purpose regulating the are.

In the drawings the electrodes are illus trated at l 2, the arc is shown at 3, the series magnet at 4, the shunt-magnet at 5, the core of the series magnet at 6, and the core of the shunt-magnet at 7. It will be seen that the core 6 of the magnet 4 is formed at each end of the said magnet and is bent at an angle so as to occupy a certain definite relation to the electrodes 1 2 and the are 3 on opposite sides thereof. The core 7 is similarly bent at the opposite ends of the magnet 5, and one portion of the core is arranged parallel and in proximity to the corresponding part of the core 6. Now in case the arc voltage rises the coil 5 takes more current, while the coil or winding 4 may be assumed to be practically unchanged in this respect, owing to the fact that the lamps are supposed to operate on constant current. The result is that the core 7 is more strongly magnetized, opposing to a greater degree the magnetic field of the core 6 and neutralizing still further the attractive efiect of the said core 6. In this way the arc recedes to a position of lower voltage. Should the arc voltage drop, the reverse action would take place, as will be readily understood.

I claim as my invention- In an alternating-current electric-arc lamp, means for regulating the resistance of the arc, such means consisting of two coils each provided with a separate core, one coil being in series with the lamp-electrodes and the other in shunt thereto, and the cores bein g so placed as to act difierentially upon each other.

2. In an alternating-current electric-arc lamp, means for regulating the resistance of the are, such means consisting of independent magnetic fields adapted to act difierentially upon each other, a coil in series with the electrodes, and the coil in shunt thereto, respectively adapted to energize the said fields.

3. In an alternating-current electricearc lamp, means for regulating the resistance of the arc, such means consisting of a coil and the core therefor, the said coil being in series with the lamp-electrodes and the arrangement being such that the 'field of the said core lengthens the are, a separate coil in shunt to the electrodes and a core for the said coil, the arrangement being such that the field of the shunt-core tends to shorten the arc, the two cores being so located that their fields act in opposition to each other.

Signed at New York, in the county ofNew York and State of New York, this 18th day of June, A. D. 1902.

MALCOLM H. BAKER.

Witnesses:

WM. H. OAPEL, GEORGE H. STOCKBRIDGE. 

